Detecting device for machines working on sheets



June 7, 1955 ETAL 2,709,960

DETECTING DEVICE FOR MACHINES WORKING ON SHEETS Filed Oct. 22, 1951Inventor's .H .fl L HAZzJJZA: Zcz

United States Patent DETECTING DEVICE FOR MACHINES WORKING ON SHEETSHans Alix, ()ifenbach (Main), and Wilhelm Winkler, Muhlheim (Main),Germany, assignors to Faber & Schleicher Aktiengesellschaft, Olfenbach(Main), Germany, a German body corporate Application October 22, 1951,Serial No. 252,558

Claims priority, application Germany October 26, 1950 7 Claims. (Cl.101-247) This invention relates to a detecting device for use inmachines operating on sheets of material, such as paper for example. Ithas particular although not exclusive reference to printing machines,especially such in which the sheets to be printed upon are fedunderlapped in a continuously moving path and in which means areprovided, to detect sheets which may be incorrectly positioned on thesupporting table, or failing altogether, by the cooperation of two ormore detecting members, through which the tripping of the printingmechanism is then initiated. For detecting, or feeling, the side edgesof the sheets preferably only one detecting device is used, while at thefront edge two of such devices are preferably employed.

In these machines the correct position of the sheets is of vitalimportance. The devices which are at present in use for detectingincorrect positions of the sheets fail in so far as they do not respondto a sheet which in the right moment lies upon the stops or guidesmarking the correct position instead of against them, or which may havetravelled too far in the direction of feed. The reason for this failure,in the known devices, usually rests in that the detecting member orfeeler which descends from above settles down upon the sheet and is,therefore, unable to contact with its cooperative member underneath.Such sheets, in the known devices, are advanced like properly positionedsheets; they consequently fail to trip the printing cylinders as theyshould and'will pass at the wrong moment, or in a wrong position, intothe machine and thereby often give rise to serious destruetions,particularly in the case of strong paper, paste board, or the likematerial.

It is, therefore, the main object of the invention to provide adetecting device for use in machines operating upon sheets, such asprinting machines, in which the aforesaid drawbacks are absent and whichwill reliably detect any wrong position which any of the sheets mayhave, before they are able to cause any harm.

Another object of the invention is to unerringly signal such incorrectposition of sheets as by immediately and automatically setting theprinting mechanism of the machine inactive and to thereby prevent thefurther advance of such sheets into the machine.

A still further object of the invention is to arrange at least one ofthe detecting members or feelers to be permanently underneath the planeof the sheet to be controlled, while at least one other member occupiesa position of rest also underneath that plane but to be moved in timedrelation to the feed of the machine around the sheet edge into itsworking position above the said plane in line with the other memberunderneath.

Still another object of the invention is the provision of electric meansin connection with the said mechanical means for initiating the trippingof the printing mechanism directly or by interposition ofoptical orother means.

The invention serves the purpose of eliminating all the disadvantages ofthe previous devices which have all been adverse to a reliable testingor detecting of the position Zfldhfihh Patented June 7, 1955 of thesheets on the supporting table and, in a preferred form for use inprinting machines, consists in an arrangement in which one or more ofthe cooperative detector members or feelers are permanently locatedbelow the underlapped path of the sheets, while their cooperatingmembers are moved in timed relation to the feed of the sheets from aposition below the plane of the sheet to be controlled, or of thesupporting table surface respectively, around the edge of the said sheetinto a position of Work, or work preparedness, above the sheet in linewith the detector member of feeler below. When in this position, thefeeler member or members are moved by mechanical or other means, whichare also driven in timed relation to the feed, into cooperation withtheir opposing members. If more convenient, both detector members aboveand below the plane of the sheet may be controlled to jointly carry outthe detecting operation or, as a further alternative, the arrangementmay be reversed in that the lower members are made to move while theupper members remain stationary.

The device according to the invention may be employed in printingpresses with underlapped feed as also in such presses in which thesheets are fed one by one into the printing mechanism of the machine.

In accordance with the invention the movable detector or feeler memberis moved into its working position at substantially the same time withthe stop or stops for the sheet to be controlled and, for this reason,is preferably also mounted upon the same shaft with the stops. In thecase of a sheet having moved beyond its stop line before the stop andthe feeler have moved into position, it will be lifted by them so thatboth feeler members come into contact with each other and therebyinitiate the tripping of the printing mechanism.

It may, and sometimes does occur, that a sheet projects but slightlybeyond the stop line. In this case the sheet crumples somewhat at theplace of the stops as soon as these move into position. The detectingdevice, normally, would not respond to such positions of the sheetbecause of the latter then lying between the two feeler members.However, to also meet such contingency two additional members may beprovided, which preferably consist of two electric contacts orterminals. positioned in the rear of the stop line. in the normal, i. e.in the correct position of the sheets these contacts will touch eachother so as to close an electric circuit, which becomes interrupted assoon as a sheet moves beyond the stop line, whereby the tripping of theprinting mechanism becomes initiated.

The members cooperating in the detecting operation may be of differentkind. They may, for instance, consist of two electric terminals, ofwhich one could be arranged to be moved together with the stops from aposition below the plane of the sheet around its edge to a position overthe underlapped path of the sheets. If a sheet should fail or bedeposited incorrectly, the two terminals, one of which is permanentlylocated below the underlapped plane of the sheets, will come intocontact with each other during the detecting operation and thereby closea circuit which initiates the tripping of the printing cylinders.

The various objects and improvements of the invention will now be moreclosely referred to in the accompanying drawings which illustrateseveral modifications of a detecting device as applicable to a printingmachine with underlapped feed of the sheets, it being understoodhowever, that the figures contained in these drawings are only given byway of example and that the means illustrated may be varied or adaptedto suit other purposes and machinery all within the scope of the claimsappended at the end of this specification. In these drawings:

Fig. 1 illustrates a detecting device which, in accordance with theinvention, is arranged to swing at least one of the detecting means froma place below the plane of the sheet to its working position above thesame.

Figs. 2 and 3 represent details of a modified form of a device similarto that shown in Fig, 1, in which two double contacts are used forcontrolling the position of the sheet. The showing of this and thefollowing figures is largeiy diagrammatic.

In the example shown in Fig. 1 the shaft, which is denominated with thereference numeral l, oscillates a ring 2 having an arm 3 in timedrelation to the feed of the sheets in the machine. Hereby the arm movesfrom the position below the plane of the sheet 4, which position isindicated in broken lines in the figure, into the position shown in fulllines, in which a contact 6, resiliently carried on a lever 55, becomestemporarily located directly over a stationary contact ortterminal 7provided within a bore of the sheet support or table.

Also in timed relation to the feed of the sheets a control lever 8raises and lowers a tappet rod 9 which is placed under the action of acompression spring 10. When in the act of feeling the edge of the sheet4 the tappet rod 9 is raised to tip the lever 5, which. is fulcrumed tothe arm 3, so that the contact 6 swings downwardly until it comes torest upon the sheet 4. If no sheet should have been delivered, or if asheet has been incorrectly placed, the contacts 6 and 7 will touch andthereby close an electric circuit over the wires connected to them andby this circuit, which immediately initiates the tripping of theprinting cylinders in a manner known per $8. In addition the detectingdevice remains locked in its circuit closing position by a plate 12 onlever 8 which takes its place in front of an abutment 11 and thusprevents the tappet rod 9 from returning into its original position.

In the modification shown in Figs. 2 and 3 the general arrangement ofthe parts must be considered to be the same, or substantially the same,as in the example shown in Fig. 1. However, in addition to the one pairof contacts 6, '7 already referred to there is provided another pair oflike contacts 13, 14 located outside the normal position of the sheet,to close an auxiliary circuit. if. the sheet to be controlled exceedsits normal position as indicated in Fig. 3, this auxiliary circuit willnot be closed and the printing mechanism will be tripped.

What we claim and desire to secure by Letters Patent of the UnitedStates is:

second-named contact, a rocking shaft for moving said arm together withsaid second-named contact in timed relation to the feed of the sheets inthe machine to a position above the plane of the table surface in linewith the said first-named contact, current conductors in connection witheach of said contacts, and power-controlled means in addition to saidswinging means in association with a reciprocating tappet rod alsooperable in timed relation to the feed of the sheets for moving, in thecase of incorrectly positioned sheets on the table, said secondnamedcontact into engagement with said first-named contact for the closing ofa circuit initiating the tripping of the printing mechanism of themachine.

3. In a detecting device for use in printing machines for printing uponsheets for detecting incorrectly positioned sheets upon the supportingtable, in combination with said supporting table and means for trippingthe printing mechanism of the machine, an electric contact arrangedstationary below the plane of the table surface, a fulcrumed lever, 21second electric contact on said fulcrumed lever swingable therewith inrelation to the first named contact and normally also located below theplane of the said table surface, a rockable arm for carrying saidfulcrumed lever and said secondnamed contact, a rocking shaft forrocking said arm together with said second-named contact in timedrelation to the feed of the sheets in the machine to a position abovethe plane of the table surface in line with said first-named contact,current COnductoi's in connection with each of said contacts, aspring-controlled tappet rod for actuating a fulcrurned lever carryingthe second-named contact, and power operated means also operating intimed relation to the feed of the sheets for reciprocating said tappetrod and thereby moving said second-named contact into touch with thefirstnamed contact and to thereby close an electric circuit in the caseof an unobstructed passage between the said contacts for initiating thetripping of the printing mechupon the sheet supporting table, incombination with 1. In a detecting device for use in printing machinesfor printing upon sheets for detecting incorrectly positioned sheets onthe feed table of the machine, in combination with said sheet feed tableand with electrically controlled means for tripping the printingmechanism of the machine, a feeler permanently located below the planeof the table surface, a second feeler swingingly arranged and normallyalso located below the said plane remote from the table. an oscillatingarm for supporting said second-named feeler, an oscillating shaft forswinging said arm together with said second-named feeler in timedrelation to the feed of sheets in the machine to a position above theplane of the table surface in line with the first-named feeler, currentconducting means in connection with each of said feelers, and means inaddition to said swinging means for moving said second-named feelers ina substantially vertical direction so as to close an electric circuitfor initiating the tripping of the printing mechanism of the machine.

2. In a detecting device for use in printing machines for printing uponsheets for detecting incorrectly positioned sheets upon the feed table,in combination with said feed table and means for tripping the printingmech anism of the machine, an electric contact arranged stationary belowthe plane of the table surface, a second electric contact swingable inrelation to the first-named contact and normally also located below theplane of the said table surface, an oscillating arm for swinging, saidsaid sheet supporting table and means for tripping the printingmechanism of the machine, a contact-member permanently located below theplane of the table surface, a second contact member normally alsolocated below said plane remote from the table, means operable in timedrelation to the feed of the sheets in the machine for swing saidsecond'named contact member around the edge of the sheet to a positionabove said plane in line with said first-named contact member, currentconductors in connection with each of said con.- tacts, means includinga tappet rod also operable in timed relation to the feed of the sheetsand to the swinging of the second-named contact for moving saidsecond-named contact member into touch with the firstnamed contactmember when no sheet is positioned between them, to close a circuit forinitiating the trip ping of the printing mechanism, and a member formaintaining the entire detecting device in its raised position over thestationary electric contact when an electric contact has beenestablished.

5. In a detecting device for use on machines operating on sheets for thedetection of incorrectly positioned sheets, in combination with asupporting table and with means for setting the operating mechanism ofthe machine at rest, a detector member stationarily located at one sideof the plane of the supporting table, a second detector member normallyalso located at the same side of said plane, means for moving saidsecond de tector member in timed relation to the feed of the sheets to apoint on the other side of said plane in line with said first detectormember and back into its initial position, means for moving saidsecond-named detector member from its position in line with said firstdetector member at right angles toward and away from the said firstdetector member, and power-operated means for effecting saidtoward-and-away movement after said second-named detector member hasbeen moved into position above the said first detector member and priorto its return movement into its initial position.

6. In a detecting device as set forth in claim 5, in which thecooperative pair of stationary and movable contact members is arrangedin duplicate so that one of said pairs responds to sheets not reachingtheir positioning marks and the other of said pairs responds to sheetspassing their positioning marks.

7. In a detecting device for use in printing machines for printing onsheets and for detecting incorrect positions of sheets on the feedtable, in combination with said feed table and with means for trippingthe printing mechanism of the machine, a feeler located stationary belowthe plane of the feed table surface, a second feeler swingably arrangedabout an axis below the said first-named feeler, means operable in timedrelation to the feed of the sheets into the machine for swinging saidsecond-named feeler to a position above the said plane in line with saidfirst-named feeler, means also operable in timed relation to the feed ofthe sheets for moving said second-named feeler in a substantiallyvertical direction toward and away from the said firstnamed feeler, andpower-driven means for efiecting said toward-and-away movement after thesaid secondnamed feeler has been moved into position above the saidfirst-named feeler and prior to the relocation of the said second feelerinto its position below the plane of the feed table surface.

References Cited in the file of this patent UNITED STATES PATENTS1,174,989 Jones Mar. 14, 1916 1,468,754 Smith Sept. 25, 1923 2,142,536Smith Jan. 3, 1939 2,221,500 Upham Nov. 12, 1940

